Two views of Bessler's wheel. Edge view at left. Face view at right. This wheel was about 12 feet in diameter.
1. Side face of wheel, covering of a light fabric.
2. Edge of wheel.
4. Two supports for the axle. The top plates suggest attachment to a ceiling.
5. Not found in picture. (Maybe it was the secret that makes it work!)
6. Four "stampers" (They move up and down to strike the box below).
7. Pegs on axle, to lift the stampers and release them.
8. Pendulum. One in front and one behind the wheel.
9. Linkage arm to drive the pendulum.
10. Linkage from axle to pendulum arm.
11. Weights on the ends of pendulum arms.
12. Pillars (to support the pendulum?)
13. Cross brace between pillars (?)
14. Peg to attach rope to axle.
15. Rope wrapped around axle.
16. Rope to lift weights.
17. Pulley attached to floor.
18. Rope (duplicate label?)
19. Wall, with open window.
20. Pulley outside window.
22. Weight being lifted.
23. Pulley support beam.
24 & 42. Brake lock attached to floor and wheel rim.
Bessler's drawings of his wheels are reasonably consistent with each other, and also consistent with eyewitness accounts. Certainly Bessler had no intention of giving away his secret in books, pamphlets or pictures, so this picture may have missing, misleading or incorrect details, and of course, whatever is inside the wheel is never shown. The scale of the sizes of parts may not be entirely consistent within the picture (even though a scale in els is shown at the bottom). Certain other details are a puzzlement.
Wheel data:Since this information comes from English translations of the source materials, I have retained the English measurement equivalents. The source materials gave dimensions in ells, presumably the Flemish ell = 27 inches = 68.58 cm.
Speculations.There's excellent agreement between the natural period of the pendulums and the unloaded speed of the wheel. This suggests that Bessler's own statement that the purpose of the pendulum was to regulate the wheel's speed may be taken as reasonable. Some have suggested that the pendulums drove the wheel (supplying continuous power to the wheel). I see no evidence to support that speculation. But these pendulums may have had a deceptive use, as we will see.
Could enough energy have been stored within the wheel itself to account for the reported demonstrations of its power? We have no certain details of what was in the wheel. Witnesses reported clanking and scraping sounds presumably from the eight 4 lb weights. The visible portion of the wheel was covered with opaque canvas fabric or oiled cloth, so no one could see the interior mechanism. No one ever reported seeing all of the eight weights said to be in the wheel. We have reports that a man who tried to stop the wheel by grabbing it at the rim was lifted off his feet, but generally no demonstrations derived any force or work from the rim of the wheel itself, only from the wheel's axle.
The visible impression the spectators got was of a massive 12 foot diameter wheel turning at 26 rev/min. Under load, it only slowed to 20 rev/min. That surely would seem impressive. How massive was the wheel? The contemporary documents don't tell us. One student of the Bessler story estimates 400 to 700 lb. Let's accept that as reasonable (for now) and see what we can conclude. We have no reason to suppose that anything but the wheel's outer shell rotated at that speed. Much of the weight inside the wheel may not have rotated at all. Surely the eight four pound weights were not the secret of the machine, for they could provide only 8 x 4 x 12 = 384 ft-lb of work even if they fell a distance of 12 feet, the diameter of the wheel. Lifting a 70 lb weight 40 feet requires 70 x 40 = 2800 ft-lb of work. Those cylindrical weights could only have been a distraction, a misdirection, to lead spectators to assume they were part of the secret of the wheels.
Many witnesses concluded that the secret to the wheel's behavior must lie within the wheel itself. At this time many people were familiar with ideas for perpetual motion wheels, and many of these had moving weights inside. Of course, these wheels could only manage less than a revoluution before stopping. Observers heard clanking sounds as the wheel turned, and Bessler sometimes removed and then replaced a 4 pound metal cylinder through a small hole in the wheel's fabric covering. He was encouraging the hypothesis that the wheel was driven by weights inside. But, as we have seen, this may have been misdirection, for eight 4 pound weights clearly could not supply the work done by the wheel.
Suppose that 600 lb of weight inside the wheel was arranged to fall slowly, giving up its potential energy as it fell a distance of, say, 6 ft. That would provide 3600 ft-lb. One source says that the wheel lifted a 16 kg (35.274 lb) box of bricks 1.5 m (4.9 feet). That would require only about 75 ft-lb of work. Some sources say the bricks weighed twice as much, 70 lb, which would require only 150 ft-lb. This demonstration doesn't sound so impressive now, does it?
Diagrams suggest a box was raised from the courtyard outside a window, using a couple of pulleys. This might be a rise of 30 to 40 feet. A 30 foot lift of 70 lb of bricks would require 2100 ft-lb. That's still less than our hypothetical "weight inside the wheel" could supply. Also, there's the possibility that the box contained "fake" lightweight bricks.
Suppose the brick box weighed only 30 lb, it would require only 1200 ft-lb to raise it 40 ft. This would be only about a third of the maximum energy you could get from a falling weight inside the wheel. I find it curious that those who analyze the Bessler story have not questioned whether the fakery might be only partly in the wheel, but also in the manner in which the demonstrations were carefully staged. In all the accounts we have no clear statement of how many assistants Bessler required for these demonstrations. We know he had at least one. But surely the task of removing the 700 lb wheel from its supports and replacing it on different supports would require more than that. My suspicion is that his assistants were carefully instructed, just as a stage magician's assistants are as much responsible for the success of an illusion as is the actor who pretends to be a magician.
When the wheel was not lifting or doing other forms of work, the stored energy in the wheel and pendulums could maintain its motion for quite a while without drawing much energy from falling weight inside. The only energy loss would be due to bearing friction. The rate of fall of such a hypothetical weight could be varied, depending upon the work being done by the wheel. If no work was being done, the wheel presumably could turn for a very long time while the weight inside fell very, very slowly. The mechanism to accomplish that may have been the most important and ingenious secret Bessler wanted to keep.
Another speculation is that the wheel, or its rather unusually thick and long axle, contained a very tightly coiled spring to store energy for later release. The only suggestive piece of evidence for a spring that some critics cited is that Bessler was once "observed" to be making an adjustment through an opening in the canvas cover of the wheel and seemed to be "tightening" something. But this evidence is flimsy, for he certainly couldn't have been "winding" a spring by manpower to store 3600 ft-lb of energy! This observation could have other explanations and I don't give it much weight. But the possibility of a spring being wound prior to a public demonstration cannot be ruled out.
Bessler swore his wheel did not use "clockwork", falling weights (like a "grandfather" clock), or springs. We have only his word on that. In the demonstration at Kassel, where one of his large wheels ran 42 days supposedly without slowing, clockwork and a wound spring could easily accomplish that and even longer, assuming that it only had to rotate the lightweight outer frame of the wheel. This wheel was not required to do work or lifting demonstrations. If those earlier demonstrations requiring work were accomplished with slowly falling weight inside the wheel, those weights could easily have been disabled (or not present at all) in the Kassel demonstration, and a spring system used instead. There are no reports that that wheel did any demonstrations requiring it to do work, and no one saw the interior of that wheel.
I haven't read everything relating to Bessler. But I wish some Bessler scholars would clear up some points for me.
The Merseberg Demonstrations.We will probably never know in detail how Bessler constructed his wheels. His own writings must be taken as self-serving, possibly engaging in misdirection. The eyewitness accounts are more interesting as sources of clues, though we must treat them with the same caution that we would treat the accounts of someone who had just watched the performance of an accomplished stage illusionist. If the performer is skillful, he has probably arranged things to encourage witnesses to assume things that weren't seen and weren't so. Bessler hid details of the mechanism of the trick, and used a knowledge of human psychology to deceive. I am reminded of the reports of witnesses at spiritualist seances of the late 19th century.
Those who wish to understand the methods of deception used in the 18th century would do well to look into the famous case of The Turk, a chess-playing automata constructed and exhibted in 1770 by the Austrian-Hungarian baron Wolfgang von Kempelen (1734–1804). It purported to be a machine designed to imitate a living beingan automaton. Automata were popular entertainment all over Europe in the 18th century, and exhibited a high degree of skill in construction. The Turk was an oriental figure seated before a chessboard on a cabinet in front of him. Doors in the cabinet were opened to reveal what appeared to be complex clockwork inside. The clockwork was wound up, and the Turk would play a game of chess with a human opponent, often winning. It was a hoax, for the cabinet, which observers swore they had seen to contain only clockwork, actually concealed a person, who manipulated the Turk from within. (The two cabinet doors were not opened simultaneously, so the hidden person had time to move out of sight behind the closed doora very simple deception common in the large illusions of stage magicians.) I mention this example to remind readers that that century had an abundance of mechanical ingenuity sometimes combined with deception. I am not suggesting that any of Bessler's demonstrations were done with a person inside the wheels. The wheel's thickness would not accomodate even a small person.
Bessler's 11 foot diameter wheel was demonstrated to 12 dignitaries on October 31, 1715. They signed, attesting to, a document that has considerable detail. This is worth quoting because the details sound more imressive than those in accounts of other demonstrations of Bessler. But still there are many details inquiring minds want to know, that this document says nothing about.
The inventor first put in motion his six ells (~11 feet) in diameter and one foot thick machine which was still resting on the same wooden support upon which it had previously been mounted. It was stopped and restarted, turned left and right as many times as was requested by the commissaries or the spectators. The machine was started by a very light push with just two fingers and accelerated as one of the weights, hidden inside, began to fall. Gradually, within about one revolution, the machine acquired a powerful and even rotation, which continued until it was forcefully brought to a stop again; the machine preserved the same rapid motion when lifting a box filled with six whole bricks weighing together about 70 pounds. The weight was lifted by means of a rope conducted through a window by means of a pulley. The box was lifted as many times as was requested.This is one of the more complete attested accounts by witnesses. At first reading it sounds impressive because many details are given. Yet it is frustrating in what it does not tell us.
One mistake that we should not make is to assume that all of Bessler's wheels, and the various demonstrations of them, all used the very same methods of deception. Some things the smaller wheels could do may not have been done by the larger wheels in the same way. The wheel that "ran two months" in a sealed castle room was apparently never used to lift weights or do other forms of work. The earler demonstrations ran for short periods (how long, the accounts don't say). But none of the earlier wheels were reported to run for two months. So the various wheels may well have operated by different methods. Indeed some critics observed that the long-running wheel could easily have run by clockwork and a wound spring, even for much longer periods of time, since it was expending no energy other than that lost to friction. Nor should we assume that this wheel weighed as much as the others, for it could easily have been only a lightweight shell, since it was not required to do any heavy lifting. From the evidence, this demonstration seems quite unconvincing to me.
So we should not speak of Bessler's "wheel" but of Bessler's "wheels", for they may have been quite different in internal mechanisms, not only different in size. To use the singular suggests that they all operated on the same principles.
Weight of the wheels.Contemporary descriptions of the wheels and accounts of the demonstrations do not tell us how much the wheels weighed. That's strange, for they repeatedly tell us other things like diameter, width, rotation rate, axle diameter, bearing diameter. Didn't anyone think the wheel weight was important? One student of the Bessler materials estimates that the larger wheels weighed 400 to 600 pounds. The account of the 1715 demonstration mentions that the wheel was moved from one set of supports to another during the demonstration. If the wheel did indeed weigh that much, we might assume that block and tackle, jacks or levers were used. Surely Bessler would not have taken the wheel apart to move the pieces in full view of spectators, for he took great pains to conceal what was inside the wheel.
What accounted for the wheel's weight? The visible portion was opaque canvas, oil-cloth or waxed linen on a lightweight wooden frame. We might generously assume the frame and axle accounted for at least 100 pounds. On at least one occasion a cylindrical metal weight was brought out from inside the wheel which an observer estimated to weigh four pounds. When the wheel rotated, eight "clunks" were heard per revolution, leading viewers to assume there were eight such weights inside, though only one had been seen. That's 32 pounds.
While eyewitness accounts give many other details, they are silent about the wheels' weight. Why didn't they consider it important? You'd think they might at least mention how many men were required to lift it. It's an example of the fact that the witnesses, even those with scientific background, weren't considering the matter in a quantitative way. Even 's Gravensande, who did some calculations, first made the common (at the time) error of using mv for energy, rather than the correct mv2/2, an error he acknowledged later.
In the document above I've mentioned some of the problems with this story, and some of the hypotheses I've seen proposed. I am not saying that I accept any of these hypotheses. Many require assumptions for which we have no historical evidence, and probably never will have. But I see nothing in the accounts to suggest that anything magical, or even anything beyond presently known physical laws, was going on. Those who want to believe that Bessler's wheel was an over-unity device assert with confidence "The evidence shows there was no possibility of fraud." On the contrary, as I read the evidence, it shows many possibilities for fraud, and strongly suggests that Bessler was a clever deceiver.
People ask me why I find this historical cold-case somewhat interesting, supposing that I might harbor the suspicion that Bessler's wheels really violated physical laws. Not at all. I have long been interested in conmen who cleverly deceive people: artists who fool the experts with forged paintings, writers who invent hoaxes. They serve a valuable social purpose, teaching us to look behind appearances, mistrust our emotions, hopes and beliefs, and to recognize what's possible and what isn't. Anyone who could fool people not only in his lifetime, but centuries after his death, as Bessler did, certainly deserves recognition.
John Collins' book.John Collins' book, Perpetual Motion, an Ancient Mystery Solved, an investigation into the legend of Bessler's wheel is a convenient source of information, for Collins has spent years with original source documents. To his credit, he relates the history straight, saving speculation for the final chapters. Chapter 12, titled "The Secret" is speculation deserving of critical analysis.
Collins tries to make the case that Bessler's wheel should not be called "perpetual motion", as that is defined today, for he thinks the wheel had an external source of power—gravity. This is a common misconception—that gravity is an energy source. Furthermore, he seems to think (as did Isaac Newton) that gravity is something like a wind, blowing through space (p. 7). This misconception leads to speculation that Bessler's wheel was something like a "gravity windmill" (my term, not John's). Not only is this a bad analogy, it is physically incorrect on several counts, and, of course, analogies ought never substitute for proofs.
Collins looks at a crucial feature of Bessler's public demonstrations, especially the later ones with large wheels (12 feet in diameter). These wheels were moved from one set of bearing supports to another during the demonstrations, ostensibly to counter suspicions that somehow a power source drove the axle through the bearings. Seems fair enough. But most accounts are silent about how the wheel was moved, which hinges on the question of how much the wheel weighed. Collins says:
According to a number of sources, before translocation of the wheel the weights were always removed. This had to be done to allow the wheel to be lifted. Orffyreus answers one of Wagner's criticisms, that this should not have been necessary, by pointing out that 'the empty wheel was so heavy that it could hardly be lifted to its new bearings. With the weights it would have needed the Devil to lift it'. (Collins, p. 180, 181)"Wagner's criticism seems valid. Eight 4 pound weights total only 32 pounds. Could that small amount of additional weight been enough to prevent the wheel being moved? That seems unlikely.
Collins assumes that two men were required to move the wheel to its new location and lift it to the new support bearings. He says that one source reports that the distance was 5 or 6 steps. That's not far, maybe 10 feet.
Hmm. One wonders whether they carried the wheel, or possibly they might have rolled it. Given the choice, rolling seems the best option. Might they have rolled it one half turn? If so, this process might well have inverted the internal mechanism of falling weight(s)(suitably latched for moving), thereby priming the system for another round of demonstrations.
Collins' understanding of physics.John Collins hints at how Bessler might have used gravity to turn his wheels. This section (p. 179) shows his fuzzy understanding of physics, making it impossible to take his speculations seriously.
The falling weight weighs the same as the rising weight but because of its position relative to their centre of balance, gravity has a greater apparent effect on it. It acts as if it weighed more than the rising weight. Simply by moving the weight further out from the centre of gravity when it is falling, and moving it closer when it is rising, allows the evice to move in a circular direction. This proves, as if we did not already know, that two weights of equal mass can alternately raise and lower each other under crtain circumstances. A small amount of momentum can be encouraged by making the difference between the positions of the two weights less, thus overcoming a tendency for them to stop in a vertical position. How you arrange for the weights to move in and out is not the issue here. I am merely demonstrating the feasibility of the idea. There is, as I have said, nothing new in this suggestion. It has been offered as a possible solution for hundreds of years and it is so obvious and elementary that it is incredible that science persists in ignoring the inherent possibilities.In this short passage Collins reveals his failure to grasp the elemtary physics principles relating to work, force, torque and momentum, principles that any student of an introductory physics course is expected to understand and be able to use correctly when analyzing physical systems. It is no wonder that "science persists in ignoring" this flawed "explanation".
The sealed castle room.I've been criticized for my comments wondering why no one mentioned the sound (or lack of sound) of the wheel when it was running in the sealed castle room. (All other wheel demonstrations were described by witnesses as very noisy.) One person said "Don't you know that castle walls are thick, and therefore soundproof?"
Indeed castle walls were thick. But rarely was a castle room without windows. After all, people relied on daylight through windows in daytime, for otherwise their only lighting would be candles and oil lamps. Original sources say that all doors and windows were closed and sealed, so we know there were windows in that room. Bessler apologists assume that all doors and windows were not only closed and sealed but also soundproofed. Still, this misses the point of my comments, for if Bessler had been honest and wanted to convince people that the wheel was running the whole while he'd have left at least a small peephole in the guarded door where anyone at any time could look in to confirm that the wheel was turning, and even hear it by putting their ear to the aperture. In short, the closed room demonstration is not convincing to me.
Bessler's demise.Bessler died in a fall from a windmill he was building. At the time he was destitute and very much in need of income. The windmill was to be a design seldom seen in Europe, a windmill with a vertical rotation axis and sails in an "S" shape (as seen from above). More conventional windmills required the wheel to be rotated to face the wind. The S design did not, but it was less efficient.
One wonders why Bessler didn't use one of his marvelous gravity wheels, which, according to contemporary accounts surely had enough power to run a grain grinding mill. It could run day after day, whether the wind was blowing or not. If he had done that he might have lived somewhat longer.
Return to perpetual futility.